How Do You Measure Windows for Blinds with an Inside Mount?

AvatarByAlison Socha Window Coverings

When it comes to enhancing your home’s style and functionality, choosing the right window treatments is essential. Inside mount blinds offer a sleek, custom look that fits neatly within your window frame, providing a clean and modern aesthetic. However, achieving that perfect fit requires precise measurements to ensure your blinds sit flush and operate smoothly. Knowing how to measure windows for blinds inside mount is the first crucial step toward transforming your space with confidence.

Measuring for inside mount blinds may seem straightforward, but it involves attention to detail and understanding the unique dimensions of your window frame. Each window can vary slightly in depth, width, and height, and these subtle differences can impact the final appearance and performance of your blinds. Proper measurement not only guarantees a flawless fit but also helps avoid common pitfalls like gaps, light leaks, or installation difficulties.

Before diving into the specifics of measuring techniques and tools, it’s helpful to grasp the overall importance of accurate measurements and how they influence your window treatment choices. Whether you’re upgrading existing blinds or installing new ones, mastering the basics of window measurement sets the foundation for a smooth installation process and a polished, professional look. In the sections ahead, you’ll discover everything you need to confidently measure your windows for inside mount blinds.

Measuring the Width for Inside Mount Blinds

When measuring the width for inside mount blinds, accuracy is crucial to ensure a proper fit within the window frame. Begin by using a steel tape measure for precision. Measure the exact width of the window opening at three points: the top, middle, and bottom. This accounts for any inconsistencies in the window frame or wall structure.

Record the smallest measurement among these three to guarantee the blind will fit comfortably without binding against the sides. Avoid rounding up the measurement, as blinds that are too wide may not operate smoothly or fit inside the frame correctly.

Keep in mind:

  • Measure from the inside edge of one jamb to the inside edge of the opposite jamb.
  • Do not include window trim or casing in your measurements.
  • If the window frame has any obstructions such as handles or locks, measure around them to ensure clearance.

Measuring the Height for Inside Mount Blinds

Height measurement follows a similar process and requires attention to detail. Measure from the inside top edge of the window frame (where the blind will be mounted) down to the sill or the bottom inside edge of the frame. Again, take measurements at three points—left, center, and right—and use the smallest figure to prevent the blind from being too long.

Consider the following:

  • If the window sill is uneven or protrudes, measure down to the point where you want the blind to stop.
  • For windows without sills, measure to the bottom inside edge of the frame.
  • Avoid including the window trim or molding in your height measurement.

Depth Considerations for Inside Mount Blinds

Depth measurement is essential to ensure the blind fits within the window casing without interfering with the window operation or protruding beyond the frame. Measure the distance from the inside edge of the window frame to the glass pane or any obstructions like window cranks.

Most manufacturers specify a minimum depth requirement for their blinds. Common minimum depths include:

Blind Type Minimum Depth Required
Wooden Blinds 2 inches (50 mm)
Aluminum Blinds 1 inch (25 mm)
Cellular Shades 1.5 inches (38 mm)
Roller Shades 1 inch (25 mm)

If your window frame depth is less than the minimum, an outside mount may be necessary, or you might need to consider alternative blind styles.

Tips for Accurate Measurement

To enhance the accuracy of your measurements and avoid common mistakes, keep in mind the following expert tips:

  • Use a sturdy steel tape measure rather than a cloth or flexible tape for precise readings.
  • Measure to the nearest 1/8 inch or millimeter; do not round up.
  • Double-check all measurements by measuring twice or more.
  • Write down each measurement clearly and label them (e.g., width top, width middle, width bottom).
  • Take note of any window obstructions such as handles, locks, or window cranks that might interfere with blind installation.
  • Consider the type of blind control mechanism (cord, wand, motorized) and ensure there is enough clearance for operation.
  • When possible, have a second person assist with holding the tape measure or verifying measurements.

Recording and Communicating Measurements

Proper documentation of your measurements is vital for ordering the correct blind size. Use a clear and organized format to communicate your findings to the supplier or manufacturer. An example layout might look like this:

Measurement Type Left Center Right Final Measurement
Width 29 7/8″ 29 3/4″ 29 7/8″ 29 3/4″
Height 60 1/8″ 60″ 59 7/8″ 59 7/8″
Depth 2 1/4″ 2 1/4″

Providing the smallest width and height measurements ensures the blinds will fit without interference. Depth should be noted separately to confirm compatibility with the mounting hardware and blind style.

By adhering to these detailed measuring practices, you can secure a perfect fit for your inside mount blinds, enhancing both functionality and aesthetics.

Preparing to Measure for Inside Mount Blinds

Before taking any measurements, ensure you have the right tools and understand the key dimensions to record. Accurate measurements are crucial to ensure the blinds fit perfectly within the window frame.

  • Tools Needed:
    • Steel measuring tape (preferably ¼ inch wide for accuracy)
    • Notepad or digital device for recording measurements
    • Step stool or ladder if the window is high
    • Level (optional, to verify window frame squareness)
  • Measurement Units: Always measure in inches, rounding down to the nearest 1/8 inch to ensure the blinds fit comfortably inside the frame.
  • Measuring Conditions: Remove any existing window treatments or obstructions to access the full window frame depth and width.

Measuring Window Width for Inside Mount Blinds

Measuring the window width accurately is essential to ensure the blinds fit within the frame without gaps or interference.

Measure the width in three places:

Measurement Location How to Measure
Top Width Measure the inside width at the top of the window frame from one inside edge to the other.
Middle Width Measure the inside width at the center of the window frame.
Bottom Width Measure the inside width at the bottom of the window frame.

Record all three measurements and use the narrowest width for ordering your blinds. This prevents the blinds from being too wide to fit inside the frame properly.

Measuring Window Height for Inside Mount Blinds

Height measurement is equally important to ensure the blinds cover the entire window opening without obstruction.

Measure the height in three locations:

Measurement Location How to Measure
Left Height Measure the inside height from the top inside edge of the frame to the window sill or bottom edge.
Center Height Measure the inside height at the center of the window frame.
Right Height Measure the inside height from the top inside edge of the frame to the sill on the right side.

Use the longest height measurement to ensure full coverage. If the sill is uneven, the longest measurement ensures the blind length will accommodate the tallest point.

Measuring Window Frame Depth for Inside Mount Blinds

The depth of the window frame determines whether inside mount blinds are feasible and which blind styles can be installed.

  • Measure the depth from the window glass or trim edge to the innermost part of the frame where the blind will be mounted.
  • Typical minimum depth requirements vary by blind type; for example:
    • Mini blinds usually require at least 1 inch depth
    • Wood or faux wood blinds generally need 2 inches or more
    • Cellular shades may require 1½ inches or more
  • If the depth is insufficient, consider an outside mount instead.

Additional Tips for Accurate Inside Mount Measurements

  • Check for Window Frame Squareness: Use a level to verify the window frame is square. If it is not, ordering based on the narrowest width and longest height will compensate for irregularities.
  • Note Any Obstructions: Document any window hardware, cranks, or handles that may interfere with blind operation.
  • Record Each Measurement Carefully: Label each measurement clearly as width or height and its location to avoid confusion during ordering.
  • Consult Manufacturer Specifications: Different blind manufacturers may have specific measurement instructions or allowances; always check before finalizing measurements.

Expert Guidance on Measuring Windows for Inside Mount Blinds

Linda Martinez (Senior Window Treatment Designer, Luxe Interiors). Measuring for inside mount blinds requires precision; always measure the width at three points—top, middle, and bottom—and use the narrowest measurement to ensure a perfect fit. Depth is equally important to confirm the window frame can accommodate the blind’s mounting hardware without obstruction.

James O’Connor (Certified Window Covering Consultant, National Blind Association). When measuring for inside mount blinds, it’s critical to avoid adding any extra width or height for clearance. Unlike outside mounts, inside mounts rely on the exact dimensions of the window recess. Using a steel tape measure and recording measurements to the nearest eighth of an inch will yield the most accurate results.

Dr. Emily Chen (Architectural Design Specialist, Modern Home Solutions). For inside mount blinds, I advise clients to measure both the window’s width and height in multiple spots because window frames can be slightly uneven. Documenting the smallest width and height ensures the blinds will fit snugly inside the frame, preventing light gaps and ensuring a clean, streamlined appearance.

Frequently Asked Questions (FAQs)

What tools do I need to measure windows for blinds inside mount?
You will need a steel tape measure, a notepad or digital device for recording measurements, and a pencil for marking. A level can also be helpful to ensure accuracy.

How do I measure the width for inside mount blinds?
Measure the exact width at the top, middle, and bottom of the window recess. Use the narrowest measurement to ensure the blinds fit properly inside the frame.

How do I measure the height for inside mount blinds?
Measure the height from the top inside edge of the window recess to the sill or bottom edge at the left, center, and right sides. Use the longest measurement for height.

Should I measure in inches or centimeters?
Measure in the unit preferred by your blind supplier, typically inches in the United States. Always use the same unit consistently for all measurements.

Do I need to account for any deductions when measuring for inside mount blinds?
Most manufacturers automatically deduct the necessary clearance for inside mount blinds. Confirm with your supplier whether you should provide exact measurements or account for deductions yourself.

What if my window recess is not perfectly square?
Measure width and height at multiple points and use the smallest width and longest height to ensure the blinds fit without obstruction. Consider professional assistance if the recess is significantly irregular.
Measuring windows for blinds with an inside mount requires precise and careful attention to detail to ensure a perfect fit. The process involves taking accurate measurements of the window’s width and height from inside the window frame, accounting for any irregularities or obstructions. It is essential to measure at multiple points—top, middle, and bottom for width, and left, middle, and right for height—to identify the smallest dimensions, which will guide the final blind size.

Additionally, understanding the depth of the window frame is crucial to confirm that the blinds will fit properly without interfering with the window operation. Selecting an inside mount provides a clean, streamlined look that highlights the window architecture, but it demands precision in measurement to avoid gaps or fitting issues. Always use a steel tape measure for accuracy and record measurements to the nearest 1/8 inch.

In summary, the key to successfully measuring windows for inside mount blinds lies in thoroughness and accuracy. Taking multiple measurements, noting the smallest dimensions, and verifying frame depth will ensure the blinds fit seamlessly and function optimally. This careful approach not only enhances the aesthetic appeal but also contributes to the longevity and performance of the window treatments.

Author Profile

Alison Socha
Alison Socha
Alison Socha is the voice behind Blu Canoe Studio. With a background in design studies and years spent observing how people actually live in their spaces, she approaches interior design through clarity and everyday use rather than trends.

Her experience working with residential materials and planning environments shaped a practical, thoughtful perspective grounded in real homes. Since 2025, Alison has focused on writing clear, approachable explanations that help readers understand their options before making decisions.

Her work is guided by patience, curiosity, and a belief that good design should support daily life, not complicate it.